More recently, auxiliary autotransfusion blood collection containers have been employed with chest drainage units which permit reinfusion of the collected blood to the patient thereby avoiding the necessity of infusing stored blood from another person and the possibility of transmitting a disease to the patient.
Some autotransfusion devices of this type have had certain problems or disadvantages associated with them. A blood collection bottle which is non-collapsible has been connected to a chest drainage unit such that suction is applied through the bottle to the plueral cavity of a patient with the bottle receiving drainage blood. In order to reinfuse the blood into the patient, the bottle must be vented to atmosphere to allow the collected blood to flow from the bottle to the patient. In such a case, air is in contact with the blood and may effect its characteristics. Also, an air filter should be used to filter air from the atmosphere into the container during infusion.
Collapsible bag blood collection containers have also been used in order to avoid the necessity and problems of venting the container during reinfusion. However, such collapsible bag-type containers have also had certain problems and disadvantages. For example, the collapsible bag requires apparatus to maintain the bag in an expanded condition during blood collection in spite of the negative pressures or suction forces within the bag. This has caused, in some cases, the bag and the bag expanding device to be complicated and expensive, and in general, such bags when expanded may take on indefinite shapes and produce indefinite volumes and produce inaccurate indications of the amount of blood collected at any time.
Because drainage fluids from the plueral cavity contain solids or semisolids, known autotransufusion devices employ a filter placed in the patient drain line. This placement of the inlet filter creates several problems in use. In most cases during the initial stages of recovery from pneumo-thoracic surgery there is some leakgage of air at the wound site. The air passes with the blood, through the filter thus producing bubbling and foaming of blood. Such foaming gradually fills the air space in the device making it more difficult to determine the amount of blood collected at any given time and also creating a problem by expelling blood as well as air when the collection bag is squeezed to expell air prior to reinfusion of the patient's blood.